Structural Responses: Single-Degree-of-Freedom (SDOF) Systems

Pressure-impulse (P-I) diagrams, which relates damage with both impulse and pressure, are widely used in the design and damage assessment of structural elements under blast loading. Among many methods of deriving P-I diagrams, single degree of freedom (SDOF) models are widely used to develop P-I diagrams for damage assessment of structural members exposed to blast loading. The popularity of the SDOF method in structural response calculation in its simplicity and cost-effective approach that requires limited input data and less computational effort. The SDOF model gives reasonably good results if the response mode shape is representative of the real behaviour. Pressure-impulse diagrams based on SDOF models are derived based on idealised structural resistance functions and the effect of few of the parameters related to structural response and blast loading are ignored. Effects of idealisation of resistance function, inclusion of damping and load rise time on P-I diagrams constructed from SDOF models have been investigated in this study. In idealisation of load, the negative phase of the blast pressure pulse is ignored in SDOF analysis. The effect of this simplification has also been explored. Matrix Laboratory (MATLAB) codes were developed for response calculation of the SDOF system and for repeated analyses of the SDOF models to construct the P-I diagrams. Resistance functions were found to have significant effect on the P-I diagrams were observed. Inclusion of negative phase was found to have notable impact of the shape of P-I diagrams in the dynamic zone.

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Subcritical bifurcation in a self-excited single-degree-of-freedom system with velocity weakening–strengthening friction law: analytical results and comparison with experiments

Nonlinear Dynamics ◽

10.1007/s11071-017-3779-4 ◽

2017 ◽

Vol 90 (3) ◽

pp. 2037-2046 ◽

Cited By ~ 29

Author(s):

A. Papangelo ◽

M. Ciavarella ◽

N. Hoffmann

Keyword(s):

Degree Of Freedom ◽

Single Degree Of Freedom ◽

Friction Law ◽

Subcritical Bifurcation ◽

Single Degree ◽

Analytical Results ◽

Comparison With Experiments

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An approach to quantify the influence of ground motion uncertainty on elastoplastic system acceleration in incremental dynamic analysis

Advances in Structural Engineering ◽

10.1177/1369433217693630 ◽

2017 ◽

Vol 20 (11) ◽

pp. 1744-1756 ◽

Cited By ~ 1

Author(s):

Peng Deng ◽

Shiling Pei ◽

John W. van de Lindt ◽

Hongyan Liu ◽

Chao Zhang

Keyword(s):

Dynamic Analysis ◽

Ground Motion ◽

Earthquake Engineering ◽

Structural Response ◽

Incremental Dynamic Analysis ◽

Degree Of Freedom ◽

Maximum Acceleration ◽

Single Degree Of Freedom ◽

Single Degree ◽

Performance Based Earthquake Engineering

Inclusion of ground motion–induced uncertainty in structural response evaluation is an essential component for performance-based earthquake engineering. In current practice, ground motion uncertainty is often represented in performance-based earthquake engineering analysis empirically through the use of one or more ground motion suites. How to quantitatively characterize ground motion–induced structural response uncertainty propagation at different seismic hazard levels has not been thoroughly studied to date. In this study, a procedure to quantify the influence of ground motion uncertainty on elastoplastic single-degree-of-freedom acceleration responses in an incremental dynamic analysis is proposed. By modeling the shape of the incremental dynamic analysis curves, the formula to calculate uncertainty in maximum acceleration responses of linear systems and elastoplastic single-degree-of-freedom systems is constructed. This closed-form calculation provided a quantitative way to establish statistical equivalency for different ground motion suites with regard to acceleration response in these simple systems. This equivalence was validated through a numerical experiment, in which an equivalent ground motion suite for an existing ground motion suite was constructed and shown to yield statistically similar acceleration responses to that of the existing ground motion suite at all intensity levels.

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